Revealing the electrochemical mechanism of the conversion-type Co3S4 in a novel high-capacity Mg-Li hybrid battery

A dendrite-less Mg anode is coupled with an insertion-type cathode to construct a Mg-Li hybrid ion battery competitive to the state of art Li-ion batteries. However, the issue of limited energy density restricts the practical application of Mg-Li hybrid battery. Herein, it is the first time to assemble an ultrahigh-capacity Mg-Li hybrid battery with spinel Co3S4 cathode and Mg anode. The particle-like Co3S4-F delivers the initial high discharge capacity of 779.8 mAh g(-1) and retains 399.5 mAh g(-1) in the 100th cycle with discharge voltage platform at 1.10 V vs. Mg2+/Mg and high energy density of 439.5 Wh kg(-1) at 0.1 A g(-1), much higher than that of reported chalcogenides in a nucleophilic APC-based Mg-Li hybrid electrolyte. The synergistic effect of hierarchical Co3S4-F micro/nano particles and APC-LiCl hybrid electrolyte pro-motes outstanding electrochemical performance of spinel Co3S4-F upon cycling. The conversion reaction of the Co3S4-F to metallic Co and sulfide Li2S contributes to ultrahigh capacity of Mg-Li hybrid battery during the discharge process. This work will pave the way for the development of the spinel chalco-genides as cathode materials for high-energy-density Mg-Li hybrid batteries. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

In this study, an ultrahigh-capacity Mg-Li hybrid battery was assembled for the first time using spinel Co3S4 cathode and Mg anode. The Co3S4-F particles delivered high discharge capacity and energy density, outperforming reported chalcogenides. The synergistic effect of Co3S4-F micro/nano particles and APC-LiCl hybrid electrolyte promoted outstanding electrochemical performance.